Refrigerator



Patented July is, 1939' REFRIGERATOR Harley E. Bixler, Schenectady, N.Y., assignor to General Electric Com New York pany, a corporation ofApplication June 28, 1935, Serial No. 28,842

9 Claims.

My invention relates to refrigerators and more particularly torefrigerato of the type provided with a cooling compartmen and anarrangement for abstracting heat therefrom while maintaining therelative humidity of theair in the cooling compartment at acomparatively high value.

Refrigerators of the type described, and particularly those designed fordomestic use, are frequently provided with a refrigerant evaporatorwhich contains a vaporizable refrigerant, the refrigerant beingvaporized by the absorption of heat from the contents of thecompartment. Even when a relatively small differential exists betweenthe temperature of the evaporator and that of the air in thecompartment, some moisture is condensed on the surface of theevaporator.

Since this surface may be quite extended in area, there is difllculty inproviding a suitable arrangement for removing the moisture therefrom.

It is an object of my invention to provide a refrigerator of the typedescribed in which the relative humidity of the air therein ismaintained at a comparatively high value and including an improvedarrangement for localizing the area on which moisture is condensedwithin the cooling compartment of the refrigerator.

Another object of my invention is to provide a refrigerator of the typedescribed in which the exterior walls of the cabinet are utilized fordissipating heatfrom a refrigerant condenser conduit and having anarrangement for miniminng the transfer of heat from such exterior wallsto the cooling compartment of the refrigerator.

Further objects and advantages of my invention will become apparentasthe following description proceeds and the features of novelty whichcharacterize my invention will be pointed out with particularity in theclaims annexed to and forming a part of this specification.

For a better understanding of my invention. reference may be had to theaccompanying drawing in which Fig. 1 is a side elevation, partly insection, of a refrigerator embodying my invention,

the central portion of the cabinet being broken away and Fig. 2 is afragmentary plan view,

partly in section, along the line 2-4 of the freezing compartment andthe evaporator therefor of the refrigerator, shown in Fig. 1.

Referring to the drawing, I have shown in .Fig. 1

closely surrounds the adjacent top portion of the shell III. A coolingcompartment I3 is formed within the cabinet, the inner walls thereofbeing formed by a rectangular sheet metal inner liner ll which isarranged in spaced relation with respect tothe outer shell in. The innerand outer walls of the cabinet thus formed are separated by suitableheat insulation IS. The cabinet is supported on a series of sheet metallegs l6. Access may be had to the interior of the cooling compartment I3through a door opening formed in the front thereof which is closed by -aheat insulated door (not shown).

The refrigerator illustrated is also provided with a freezingcompartment which is located within the cooling compartment and isseparated therefrom by a heat insulated wall ll, which surrounds thebottom and two side walls of the freezing compartment l8. The exteriorsides of the wall II are covered by a sheet metal casing i 9 made ofsteel or the like which is exposed to the interior of the coolingcompartment IS. The edges of the casing i9 are provided with aperipheral flange 20 which extends parallel to the adjacent portion ofthe inner liner l4 and is separated therefrom by a gasket 2| of heatinsulating material such as rubber which extends entirely about theflange 20. The casing i9 is secured to theinner liner I4 by a series ofbolts 22 which pass through the flange 20, gasket 2 I, and adjacentportion of the inner liner I4. The open front of the freezingcompartment I8 is closed by a heat insulated door 28 which is mounted onhinges 24 arranged atthe side of the opening in the front of thefreezing compartment. The door 23 is retained in its closed position bya suitable spring catch 25, one end of which is secured to the adjacentportion of the casing Ill.

The re rigerator cabinet described above is provided wi h arefrigerating machine which includes an arrangement for maintaining theair in the cooling compartment at a temperature suitable for preservingfoods such as vegetables and the like, preferably about 45 F., and an'arrangement for maintaining the interior of the freezing compartment ata temperature suitable for preserving meat andthe like, and for freezingice or similar articles, preferably about 20 F. The refrigeratingmachineforthe cabinet described includes a refrigerant circulatory unit which,in the illustrative form of my invention, is a motor driven refrigerantcompressor mounted ina hermeticallysealedsteel casing 28, which isembedded in the heat insulation above the top wall of the coolingcompartment ii. The casing 28 contains a body of. lubricant forlubricating the motor and compressor. Gaseous refrigerant compressed bythe motor driven compressor contained in the casing 26 is dischargedtherefrom through a conduit 21 and passes therethrough to a condenserconduit 28. The condenser conduit 28 extends about the interior sides ofthe four side walls of the shell I 0 and is arranged in good thermalcontact therewith. The conduit 28 is preferably soldered, or otherwiserigidly secured, to the inner surface of the outer shell Ill. The outershell I0 is thus utilized to dissipate heat from the compressed gaseousrefrigerant in the conduit 28 and formsa condenser surface. Heat passesfrom the refrigerant in the conduit 28 thr ugh the walls thereof to theouter shell l0 an the latter is cooled by the surrounding air whichcirculates upwardly thereover due to natural draft.

The compressed gaseous refrigerant flowing through the condenser conduit28 is liquefied by the cooling action described above and therefrigerant thus liquefied passes through a conduit 29 to a flowcontrolling float valve 30. Liquid refrigerant is supplied from the flowcontrolling float valve 30 to an evaporator conduit 3|, which isutilized to abstract heat from the cooling compartment |3. Theevaporator conduit 3| extends about three side walls of the inner linerM in good thermal contact therewith, being soldered, or otherwiserigidly secured, to the adjacent outer surface of the inner liner l4,the inner liner being thus utilized to form an evaporator coolingsurface. A portion of liquid refrigerant passing through the evaporatorconduit 3| is vaporized by the absorption of heat from the contents ofthe cooling compartment. Since the evaporator conduit 3| is in thermalcontact with a large portion of the side walls of the inner liner M, anevaporator having a relatively large area presented to the interior ofthe cooling compartment l3 isthus provided. The inner liner I4 is thusmaintained at a temperature of approximately 35 F. to 40 F. when the airin the interior of the cooling compartment I3 is at a temperature of 45F. It is possible to cool the air within the cooling compartment |3while maintaining such a small temperature differential between it andthe surface of the evaporator, because of the relatively large area ofthe evaporator surface. It is advantageous to maintain the temperaturedifferential between the evaporator surface and air within the coolingcompartment as small as possible in order to minimize the condensationof moisture on the surface of the evaporator and, hence, minimize thedehydration of articles stored in the cooling compartment. With thearrangement described, the relative humidity of the cooling compartmentl3 may be maintained at between and It has been found that it isparticularly important to maintain the relative humidity of the air inthe cooling compartment at a comparatively high value when vegetables orsimilar articles are preserved therein since the dehydrapartment, sinceheat flowing through the insulated side walls of the cabinet from thewarmer air on the exterior thereof reaches the evaporator before it hasan opportunity to warm the contents, of the cooling compartment. If theheat thus leaking into the cabinet was first transferred to the airwithin the cooling compartment and then to the evaporator, it would benecessary to maintain the evaporator at a lower temperature, because ofthe greater amount of heat to be absorbed thereby from the air withinthe cooling compartment. In the arrangement which I have provided,however, the heat leaking through the insulation l5 from the shell |0 isabsorbed by the evaporator 3| before reaching the air in the compartmentl3. This factor is of particular importance in a refrigerator of thetype illustrated in which the exterior walls of the cabinet are utilizedto dissipate heat from the refrigerant condenser conduit 28. Since theexterior side walls are utilized in this manner, they are maintained ata temperature above that of the surrounding air and, hence, somewhatmore heat flows from the exterior walls through the insulation I5 towardthe cooling compartment 3. The evaporator arrangement, which I havedescribed, in which the evaporator forms the side walls of the coolingcompartment, effectually prevents the heat from the exterior side wallsof the cabinet reaching the interior of the cooling compartment l3.

vaporized and gaseous refrigerant are discharged from the evaporatorconduit 3| through a conduit 32 and pass therethrough to a differentialpressure valve 33. The differential pressure valve 33 connects theevaporator conduit 3| in series with a flooded type evaporator 36, whichis located in the freezing compartment Ill. The pressure differentialvalve 33 maintains a predetermined differential in pressure between thetwo evaporators, such as to maintain the desired temperature in thecompartments |3' and I8. A higher pressure and, hence, a highertemperature is maintained in the evaporator conduit 3| than in theflooded evaporator located in the freezing compartment l8. Liquid andvaporized refrigerant passing through the differential pressure valve 33flow through a conduit 34 to the inlet 35 of a flooded type evaporator36. The evaporator 36 is of the sheet metal type and the walls thereofare formed by inner and outer portions or sheets of steel or the like 31and 38, respectively, which are substantially L-shaped in cross section.The sheets 31 and 38 are provided with complementary indentations 33 and40, respectively, which form a longitudinal cylindrical header 4|adjacent the top of the side wall of the L-shaped evaporator 36. Aseries of corrugations 42 formed in the outer sheet 38 cooperate withthe inner sheet 31 to form a series of refrigerant circulatory passages43 communicating with the header 4| below the normal liquid levelthereinl The passages 43 thus formed extend down the side wall of theevaporator 36 and across the bottom wall thereof. The sheets 31 and 38are welded or otherwise rigidly secured together about the edges thereofand between the indentations and corrugations formed therein. Thewelding may be a line weld or a series of closely spaced spot welds.

The evaporator 36 is flooded with liquid rei'rigerant, the header 4|being normally maintained about half full of liquid refrigerant. Thevaporized refrigerant discharged into the passages 43 from the conduit34 moves upwardly to the header 4| and aids in inducing a rapidcirculation of liquid refrigerant in the passages C3. The liquidrefrigerant in the header 4| and refrigerant circulatory passages 43 isvaporized by the absorption of heat from articles contained in thefreezing compartment l8 and the vaporized refrigerant is collected inthe header. above the level of the liquid refrigerant therein. Thevaporized refrigerant thus collected in the header ll is returned to themotor driven compressor in the casing 26 through a suction conduit whichcommunicates with the header ll above the normal liquid level therein.The conduit 44 communicates with the casing 26 above the level oflubricant therein, and the vaporized refrigerant flows from the casingtothe intake of the compressor in the casing.

The edges of the inner sheet 31 of the evaporator 36 adjacent the innerliner ll are provided with a peripheral flange 45, which is separatedfrom the adjacent portion of the inner liner ll by gasket 46 of heatinsulating material such as rubber. The flange]! is secured to the innerliner I 4 by a series of bolts 41 which pass through the flange .45,gasket 46, and inner liner ll through the door opening closed by thedoor 23 and conveniently supported on the flat bottom of the freezingcompartment formed by the evaporator 36. Since the interior of thefreezing compartment I8 is ordinarily maintained at a temperature below32 F., preferably at about 20 F., ice or the like may be readily frozentherein, and meats or similar articles, which are preferably preservedat such low temperature, may be stored therein. Trays containing wateror other material to be frozen may be placed in direct thermal contactwith the inner surface of the evaporator Ii, thus insuring a rapidtransfer of heat.

The thickness and character of the heat insulation ll of the wallsurrounding the cooling compartment II are so proportioned that thetemperature gradient therethrough, between the evaporator 38 and thecasing It, will be such as to maintain the casing I! at a temperatureclose to but somewhat below the temperature of the other interior wallsof the cooling compartment II. When'the walls of the inner liner ll aremaintained at 40 F. at least a portion of the casing I! may bemaintained atv about 35 F.

' In this way, a surface is provided within the cooling compartment I!on which the condensation of moisture will be localized since thissurface is at a lower temperature than any other surface within thecompartment. It is also desirable that this surface, on-whichcondensation is to be localized, should be maintained above 32 F., inorder that no frost will be formed-thereon. It will be understood thatthe area of the cold surfaceon which condensation is localized may bereduced as the temperature thereof is lowered.

By such an arrangement, the remaining side, top, and bottom walls of thecooling compartment I! are maintained in a dry condition andthe'moisture which collects or vaccumulates on the casing ll may beconveniently collected in a removable drip tray 48, which is slidablysupcollected on the inner surfaces thereof is meltedand'the resultingmoisture-may drain through the conduit 5| to the drip tray 48.

Although the casing I9 is normally maintained at a temperature belowthat of the remaining side walls of the cooling compartment IS, in orderto localize the condensation of moisture thereon, the temperature of thecasing is maintained sumciently close to the temperature prevailing inthe cooling compartment, as pointed out above, in order that excessivecondensation of moisture on the casing, and, hence, excessive loweringof the relative humidity within the air of the cabinet is avoided. Itwill thus be seen that I have provided an arrangement by which thehumidity of the air within the cooling compartment i3 is maintained at acomparatively high value and yet in which the condensation of moisturetherein is localized in such manner as to facilitate the removalthereof.

.While I have shown a particular embodiment of my invention inconnection with a compression type refrigerating machine, I do notdesire my invention to be limited to the particular construction shownand described and I intend, in the appended claims, to cover allmodifications within the spirit and scope of my invention.

What I claim as new and desire to secure by Letters Patents of theUnited States is:

1. A refrigerator comprising a heat insulated cooling compartment and afreezing compartment, an extended evaporator presenting a heat ment tosaid second evaporator and to maintain the temperature of at least aportion of said wall close to and slightly less than the temperature ofthe remaining walls in said cooling compartment to localize thecondensation ,of moisture on said portion of said wall.

2. A refrigerator comprising a heat insulated cooling compartment and afreezing compartment, an extended evaporator presenting a heat exchangesurface of relatively large area for abstracting heat from said coolingcompartment and forming at least a portion of one side wall of saidcooling compartment, a'second evaporator for cooling said freezingcompartment, means ineluding a wall forpreventing the circulation of airfrom said cooling compartment over the surfaces of said secondevaporator, said wall being exposed to the air in said coolingcompartment and being arranged to limit the flow of heat from saidcooling compartment to said second evaporator and to maintain thetemperature of at leastv a portion of said last mentioned wall close toand slightly less than the temperature of the remaining interior wallsof said cooling compartment to localize the condensation of moisture onsai portion of said last mentioned wall.

3. A refrigerator comprising a heat insulated cooling compartment and afreezing compartment, an extended evaporator presenting a heat exchangesurface of relatively large area for abstracting heat from said coolingcompartment, a second evaporator for cooling said freezing c'ompartment,said second evaporator beingflof the flooded type and having a headerand means including a plurality of passages communicating with saidheader below the normal liquid'level therein for circulating liquidrefrigerant, said last mentioned means including a horizontal portionfor supporting articles to be frozen, a wall for preventing thecirculation of air from said cooling compartment over the surfaces ofsaid second evaporator, said wall being exposed to the air in saidcooling compartment and being arranged to limit the flow of heat fromsaid cooling compartment to said second evaporator and to maintain thetemperature of at least a portion of said wall close to and slightlyless than the temperature of the remaining walls in said coolingcompartment to localize the condensation of moisture on said portion ofsaid wall.

4. A refrigerator comprising a heat insulated cooling compartment and afreezing compartment, an extended evaporator presenting a heat exchangesurface of relatively large area for abstracting heat from said coolingcompartment, a second evaporator for cooling said freezing compartment,means including a sheet metal casing exposed to the interior of saidcooling compartment for preventing the circulation of air from saidcooling compartment over the surfaces of said second evaporator, andmeans limiting the flow of heat through said sheet metal casing to saidsecond evaporator for maintaining the temperature of at least a portionof said sheet metal casing close to and slightly less than thetemperature of the remaining walls in said cooling compartment tolocalize the condensation of moisture on said portion of said casing.

5. A refrigerator comprising a cabinet having a heat insulated coolingcompartment, an extended evaporator presenting a heat exchange surfaceof relatively large area for abstracting heat from said coolingcompartment, a second evaporator located in said cabinet, meansincluding a wall extending about said second evaporator for preventingthe circulation of air from said cooling compartment over said secondevaporator and forming a freezing compartment in which said secondevaporator is located, said wall being exposed to theair in said coolingcompartment and being arranged to limit the flow of heat from saidcooling compartment to said second evaporator and to maintain thetemperature of at least a portion of said wall close to and slight- -lyless than the temperature of the remaining walls in said coolingcompartment to localize the condensation of moisture on said portion ofsaid wall.

6. A refrigerator comprising a heat insulated cooling compartment, asheet metal inner liner forming the inner walls of said coolingcompartment, an L-shaped evaporator located within said inner liner,said evaporator including complementary L-shaped inner and outerportions of sheet metal deflningia refrigerant circulatory passagetherebetween, means for securing the upper and lower edges of saidL-shaped evaporator to the adjacent portions of said inner liner todefine a freezing compartment having an opening in the front thereof, atleast one of said portions of sheet metal having an integral rearportion forming a rear wall of said freezing compartment, and means forlimiting the transfer of heat from said cooling compartment to saidevaporator.

7. A refrigerator comprising a heat insulated cooling compartment, asheet metal inner liner forming. the inner walls of said coolingcompartment, an L-shaped evaporator located within said inner liner,said evaporator including complementary L-shaped inner and outerportions of sheet metal defining a refrigerant circulatory passagetherebetween, at least one of said portions of sheet metal beingprovided with inwardly extending flanges along the upper and lower edgesthereof lying adjacent the top and side walls respectively of said innerliner, said evaporator co-operating with said liner to define a freezingcompartment, a gasket of heat insulate ing material positioned betweeneach of said flanges and the adjacent portions of said inner liner,means for securing said flanges and gaskets and adjacent portions ofsaid inner liner together, and a heat insulated wallextending about theexterior sides of said evaporator.

8. A refrigerator comprising a heat insulated cooling cdmpartment, anextended evaporator presenting a heat exchange surface of relativelylarge area for abstracting heat from said cooling compartment, saidevaporator forming a portion of at least one wall of said coolingcompartment, means for maintaining a temperature of a portion of a wallof said cooling compartment close to and slightly less than thetemperature of the remaining walls of said cooling compartment tolocalize the condensation of moisture on said portion of said wall, saidportion of said wall constituting at least a part of the upper inner surface of said cooling compartment, and collecting means adjacent saidportion of said wall for receiving moisture condensed on said portion ofsaid wall. v

9. A refrigerator comprising a heat insulated cooling compartment, anextended evaporator presenting a heat exchange surface of relativelylarge area for abstracting heat from said cooling compartment, means formaintaining the temperature of said extended evaporator above freezing,and means including a heat exchange surface of somewhat lowertemperature than the surface of said extended evaporator for localizingthe accumulation of moisture in said cooling compartment.

HARLEY H. BIXLER.

